Hybrid power using thermionics

Spark Thermionics is developing transformative heat-to-electricity generation systems based on thermionics. In a thermionic energy converter, electrons evaporate from a hot electrode, the emitter, into a vacuum gap and are collected by a cooler electrode, the collector, to generate electric current. In the 1960-1970s, multiple groups reported thermionic converters with power densities >10 W/cm2 (>100 kW/m2), conversion efficiencies of ~10-15%, and lifetimes over 5 years. However, most of this progress was tied to the US space-nuclear program which ended in 1973; thermionics has never fully shaken the perception of being “tried before”. Spark has now demonstrated a new generation of device that is much thinner than previous designs under programs with the Air Force and NASA. Under this proposed project, Spark plans to assess the impact of this new thinner device design on potential generation for onboard capabilities, lightweight fuel-efficient platform design aligned with Operational Energy S&T needs expressed by the US Army. Specifically, we propose to address enhancement of Group I/II endurance/range from adaptation of these thinner devices.